The present invention relates to a shift lock device which may preclude a shift lever from operating under certain conditions when the shift lever is positioned in a parking position.
A conventional shift lock device of a shift system generally includes a locking mechanism, an actuator (for example, a solenoid), a control switch and a controller (for example, a microcomputer). The locking mechanism has a locking plate to be engaged with an engagement pin provided on a shift lever when the shift lever is positioned in a parking position, and has a stopper plate to restrict the motion of the locking plate. The stopper plate is moved between a locking position and a released position by the action of the actuator. The control switch detects the position of the shift lever and generates a signal corresponding to the position of the shift lever. The controller is provided with the signal from the control switch. The controller is further provided with signals from an ignition switch, a foot brake and other components. The controller controls the actuator based on these signals.
When the shift lever is positioned in the parking position, the locking plate is engaged with the engagement pin and is lifted up. The actuator is normally deenergized so that the stopper plate remains in the locking position which may prevent downward motion of the locking plate. Therefore, the stopper plate may preclude downward motion of the engagement pin, thereby preventing operation of the shift lever. Upon energization of the actuator, the stopper plate is moved to the released position which may allow downward motion of the locking plate. As a result, the engagement pin can be moved downward to operate the shift lever.
In the shift lock device, the construction elements thereof are generally separately mounted on a shift lever supporting plate and a detent plate of the shift system.
In the prior art, a shift lock device has been developed, as in Japanese Laid-Open Utility Model Publication No. 2-458. In this shift lock device, the control switch is integrated into the locking plate of the locking mechanism to form an integral part which is mounted on the detent plate together with the actuator.
However, such arrangement of the construction elements of the shift lock device cause fluctuations of a relative position of the locking mechanism and the actuator, thereby causing fluctuations of a relative position of the locking plate and the stopper plate moved by the actuator. To compensate the fluctuations of the relative position of the locking plate and the stopper plate for preventing relative interference therebetween in motion, these members are generally sized so as to loosely interact each other or are adapted to move over a wide moving range. This may require an increased space to mount the shift lock device.
Further, when the controller is separated from the control switch, complicated wiring is required to electrically connect therebetween. This may lead to decreased reliability and durability of the shift lock device.
Other prior art shift lock devices are found, for example, in Japanese Laid-Open Utility Model Publication No. 1-171722.